1. Field of the Invention
The present invention relates to a target substance-detecting element having a nonspecific adsorption-preventing capability, a target substance-detecting kit and a structure forming the target substance-detecting element.
2. Description of the Related Art
As a technique to detect a target substance in an analyte, intermolecular interactions have hitherto been utilized. As a technique utilizing intermolecular interactions, generally adopted is a method in which the molecules of the interaction counterpart of the target substance are immobilized as a capturing molecule on the surface of a substrate, and a target substance-containing analyte is brought into contact with the surface to cause the reaction of the target substance with the interaction counterpart.
In the quantitative measurement of the target substance undergoing interaction with the immobilized capturing molecule, depending on the nature of the substrate surface or the immobilization method, there is an unfavorable possibility that some substances nonspecifically adsorbed on the substrate surface are simultaneously detected in addition to the target substance interacting with the capturing molecules. This possibility constitutes a cause for degradation of the lowest detection sensitivity in a sensor required to conduct trace amount detection. Accordingly, there has been demanded a method which exclusively detect a target substance while suppressing nonspecific adsorption.
As a technique to prevent the nonspecific adsorption on the substrate surface, in “Biomacromolecules,” 2004, 5, pp. 2308 to 2314, there is disclosed a technique in which by using MPC (2-methacryloyloxyethyl phosphorylcholine) as a monomer on a silicon substrate surface, the MPC polymer is formed on the substrate surface in a high density on the basis of an atom transfer radical polymerization so as to prevent nonspecific adsorption of proteins and to prevent adhesion of cells.
On the other hand, in “Biomacromolecules,” 2006, 7, pp. 3311 to 3315, there is disclosed a technique in which by using CBMA (2-carboxy-N,N-dimethyl-N-(2′-methacryloyloxyethyl)ethanaminium inner salt) as a monomer, the CBMA polymer is formed on the SPR (Surface Plasmon Resonance) sensor surface in a high density on the basis of an atom transfer radical polymerization, and thereafter a capturing molecule is immobilized to the carboxyl groups that are the side chain functional groups of the CBMA polymer, and thus the target substance is detected while nonspecific adsorption of contaminants is being prevented.
However, in any of the above-described techniques, the capability of preventing the nonspecific adsorption cannot be said to be sufficient, and there have hitherto been demanded target substance-detecting elements having a further enhanced capability of preventing nonspecific adsorption.